Pump and method for changing the pumping capacity of a pump

ABSTRACT

A pump for fluids includes a pump housing, a power source enclosed within the housing, a drive shaft connected to the power source, at least one pump inlet arranged in the pump housing, a pump outlet arranged in the pump housing, a first impeller arranged within a first impeller chamber and rotated by the drive shaft, and a second impeller arranged within a second impeller chamber and rotated by the drive shaft. The pump is changeable between a first configuration in which the first and second impeller are arranged in parallel to provide a high pumping capacity, and a second configuration in which the first and second impeller are arranged in series to provide a pump with less pumping capacity.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims benefit to EP 15187667.9, filed Sep. 30, 2015,the contents of which is hereby incorporated herein by reference.

BACKGROUND

Field of the Invention

The present invention relates to a pump for a fluid, and a method forchanging the pumping capacity of a pump.

Background of the Invention

Different types of pumps are used within many different technical areas.One particular area where reliable and efficient pumps are essential isin mines or pits where pumps are running more or less constantly todrain water from the mine or pits.

When emptying flooded mines or pits there is a need to start with a pumpwith a high flow (Low head), i.e. a pump with high pumping capacity, toquickly drain as much water as possible in a short period of time. Whenpumping continues and the water level continually gets lower the needhowever is changed to a pump with a high head, i.e. a pump with lowerpumping capacity, since the pump is only required to maintain thedrained conditions in the mine or pit. Mostly the pump, when the drainedcondition is achieved, is replaced by another pump with reduced pumpingcapacity, i.e. a pump with a lower flow that is adapted for therequirements relating to maintaining the drained state in the mine orpit. No pumps available on the market today are adaptable to thesecompletely different operational conditions and requires that more thanone pump must be used to provide an efficient solution in the describedsituation. The additional pump, or pumps, generates additional work forthe pump operator and requires that more than one pump are provided andmaintained to work as intended.

SUMMARY

There is consequently a need for an improved pump that is able to workefficiently during different operational conditions.

The present invention relates to a pump for fluids that to at least someextent fulfils the needs defined above. The pump for fluids according tothe invention comprises a pump housing; a power source (8) enclosedwithin said housing (11); a drive shaft connected to the power source(8); at least one pump inlet (14) arranged in the pump housing; a pumpoutlet (15) arranged in the pump housing; a first impeller arrangedwithin a first impeller chamber and rotated by said drive shaft, and asecond impeller arranged within a second impeller chamber and rotated bysaid drive shaft, wherein the pump is changeable between a firstconfiguration in which the first and second impeller are arranged inparallel to provide a high pumping capacity, and a second configurationin which the first and second impeller are arranged in series to providea pump with less pumping capacity.

The pump according to the invention fulfils the needs defined abovesince the possibility to change between the two configurations makes itpossible to adapt the pumping capacity and characteristics of the pumpto different required working conditions. This is very advantageoussince the need for additional pumps with different pumping capacity andcharacteristics is eliminated, or at least reduced. The pump accordingto the invention is usable either in the first configuration, i.e. highpumping capacity and low head, and the second configuration, i.e.reduced pumping capacity and high head, when a higher pressure isdesired.

The pump is furthermore advantageous since the power source is protectedby the pump housing, and the pump could be designed in a compact andpractical way with the power source integrated within the pump housingsuch that the pump could be moved easily in one piece.

The pump according to the invention furthermore reduces the need fortransportation, installation, service and investments in additionalpumps since different pumping characteristics could be provided by onesingle pump.

In one embodiment of the pump, the first and second impellers arearranged at different positions along the drive shaft. This designensures that the desired function is achieved with a limited number ofdifferent components in the pump, i.e. only one power source and driveshaft that is arranged to power both impellers.

In one embodiment of the pump, the power source is an electrical orhydraulical power source arranged within the pump housing. Electricaland hydraulic power sources are reliable and ensure that the pump willwork as intended for a long period of time.

In one embodiment of the pump, the housing encloses the power source andprevents that the fluid reach the power source. This embodiment isfavourable since the entire pump could be lowered into the flooded mine,pits, cavity or compartment that need to be drained without the risk ofbeing damaged.

In one embodiment of the pump, the first impeller chamber, in which thefirst impeller is arranged comprises at least one first impeller chamberinlet and at least one first impeller chamber outlet, and the secondimpeller chamber, in which the second impeller is arranged, comprises atleast one second impeller chamber inlet and at least one second impellerchamber outlet, wherein, in the first configuration, the at least onefirst and second impeller chamber inlets are in fluid connection withthe pump inlet, and the at least one first and second impeller chamberoutlets are connected to the pump outlet, and, in the secondconfiguration, the at least one first impeller chamber outlet is influid connection with the at least one second impeller chamber inlet andthe at least one second impeller chamber outlet is connected to the pumpoutlet. This configuration of the different components in the pumpprovides a pump that is easily changed between the first and the secondconfiguration, and provides a robust and reliable pump that is able tolast for a long period of time.

In one embodiment of the pump, the first and second impeller chamberoutlets are connected to conduits extending within the pump housing pastthe electrical power source to cool the electrical power source andprevent damages to the power source due to increased temperature withinthe pump housing.

In one embodiment of the pump, the at least one first and secondimpeller chamber outlets are connected to an annular space definedwithin the housing around the electrical power source to cool theelectrical power source. This embodiment is advantageous since theannular space provides efficient cooling to electrical power source.

In one embodiment of the pump, the first and second impeller chambereach comprises two chamber outlets arranged adjacent to the outerperiphery of the first and second impeller in radially oppositepositions around the impeller. The two outlets of each impeller chamberarranged in radially opposite positions around the impeller reduces theloads on the impeller, the shaft and bearings since the forces from thewater on the pump components are working in opposite directions.

In one embodiment of the pump, the outlets of the second impellerchamber are arranged between the outlets of the first impeller chamberin the pump housing. This embodiment is favourable since the fouroutlets extending past the electrical power source will provideefficient cooling to the power source, especially in when the pump isoperated in the first configuration since water is flowing in all fouroutlets when the impellers are operated in parallel.

In one embodiment of the pump, the pump housing comprises a housingbottom structure that is removably attached to the housing. Thisembodiment is favourable since the removable bottom structure providesexcellent access to interior of the housing.

In one embodiment of the pump, the pump furthermore comprises at leastone redirection element, a covering element and at least one pluggingplate that are fitted when the pump is operated in the secondconfiguration.

In one embodiment of the pump, the redirecting element and the coverelement are arranged to connect the first impeller chamber outlet withthe second impeller chamber inlet.

In one embodiment of the pump, the redirecting element is designed toconnect the first impeller chamber outlet to the second impeller chamberinlet and direct the flow of fluid from the first impeller chamber tothe second impeller.

In one embodiment of the pump, the covering element has the shape of aplate and is intended to be arranged covering the second impellerchamber inlet. This embodiment is very favourable since the coveringelement provides a reliable sealing of the second impeller chamberinlet.

The invention furthermore relates to a method for changing the pumpingcapacity of a pump comprising: a housing; a power source; a firstimpeller and a second impeller. The method comprises the steps ofchanging the pump from a first configuration in which the first andsecond impeller are arranged in parallel to provide a high pumpingcapacity, to a second configuration in which the first and secondimpeller are arranged in series to provide a pump with less pumpingcapacity, or changing the pump from the second configuration to thefirst configuration.

The different embodiment described above could of course be combined andmodified in different ways without departing from the scope of theinvention that will be described more in detail in the detaileddescription.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be explained in more detail hereinafter withreference to the drawings.

FIG. 1 illustrates a side view of a pump.

FIG. 2A illustrates a top view of the pump in FIG. 1.

FIGS. 2B and 2C illustrates a cross sectional view of a pump accordingto the invention in the first configuration.

FIG. 2D illustrates an exploded view of the pump arranged in the firstconfiguration.

FIG. 3A illustrates a top view of the pump in FIG. 1.

FIGS. 3B and 3C illustrates a cross sectional view of a pump accordingto the invention in the second configuration.

FIG. 3D illustrates an exploded view of the pump arranged in the secondconfiguration.

DETAILED DESCRIPTION OF THE EMBODIMENT

In FIG. 1 a side view of a pump 10 according to the invention isillustrated. The pump is intended for pumping fluids such as for examplewater. The pump comprises a pump housing 11 enclosing and protecting thedifferent parts of the pump. The pump housing has a substantially flatbottom structure 12 intended to be arranged towards a support surfacesuch as for example the ground surface of a mine or pit that needs to bedrained.

The illustrated embodiment of the pump housing has a substantiallycircular cross section with a smaller radius towards the upper end ofthe pump. The upper end of the pump housing is ended by a top surface 13slightly angled in relation to a plane transverse to the vertical axis Vof the pump. Furthermore, since the illustrated pump comprises anelectrical power source arranged within the housing, at least one cablefor power supply to the pump extends through the pump housing. The atleast one cable is not illustrated FIG. 1 but is preferably arrangedclose to the upper end of the pump housing. The pump could however alsobe embodied with the power source arranged separately from the pump anda drive shaft extending from the power source to the pump.

In the lower part of the housing a perforated section 14, i.e. pumpinlet, is arranged to let water enter the water pump. The perforatedsection prevents that undesired objects enter the pump with the waterwhich could affect the operation of the pump and eventually damage thepump. The total area of the perforated section is selected to ensurethat enough water always is able to pass through the perforations andenter the water pump. The size of each opening in the perforated sectioncould be adapted to the intended use of the pump to prevent differentlysized objects to pass.

Close to the upper end of the housing an outlet pipe 15 is arranged. Theoutlet pipe is intended for the fluid from the pump and is ended by anattachment device 16 to make it possible to connect a pipe with suitablelength and dimension to direct the fluid from the pump to the intendedplace where the drained fluid could be extracted.

The pump according to the invention is designed to be able to operateeither in a first configuration or in a second configuration. When thepump is operated in the first configuration, i.e. the pump operating ina “low head” setup, the pump will have a high pumping capacity and whenoperated in the second configuration, i.e. the pump operating in a “highhead” setup, the pump will have a reduced pumping capacity.

FIG. 2A illustrates a top view of the pump in FIG. 1 and the position ofthe cross sectional views in FIGS. 2B and 2C. The pump illustrated inFIG. 2A-2C is arranged in the first configuration.

The pump 10 comprises an electrical power source/electrical motor 8arranged within the upper part of the housing in the center of thehousing. The electrical power source is arranged to power the pump via adrive shaft 6 extending substantially parallel to the vertical shaft ofthe pump downwards from the electrical motor. The size and power of thepower source is selected to correspond to the size and desired pumpingcapacity of the pump.

The rotating drive shaft 6 extends downwards to a first pump device 18and a second pump device 17 arranged along the drive shaft below theelectrical motor. The second pump device is arranged closest to thebottom structure 12 of the pump housing, and the first pump device 18arranged between the first pump device 17 and the electrical motor 8.

The second pump device 17, illustrated in FIG. 2C, comprises a secondimpeller 19 rotatably arranged within a second impeller chamber 20. Thesecond impeller is arranged to be rotated by the drive shaft. The secondimpeller chamber has at least one impeller chamber inlet 21 arranged onthe bottom side of the second pump device 17, i.e. the impeller chamberinlet 21 is arranged close to the bottom structure 12 of the pumphousing 11 and in fluid connection with the space defined within thepump housing inside the perforated section 14 of the housing 11. Thesecond pump device furthermore comprises two impeller chamber outlets 22arranged adjacent to the outer periphery of the second impeller inradially opposite positions around the second impeller 19. The secondimpeller 19 has the shape of an impeller disk with guiding elementsarranged on one side to generate a flow of fluid through the second pumpdevice. The outlets 22 are curved upwards and connected to second volutetubes 28 extending from the outlets to conduits 23 extending within thepump housing to the outlet pipe 15 past the electrical power source 15such that the fluid flowing through the conduits cools the electricalpower source when the pump is running.

The first pump device 18, best illustrated in FIG. 2B, is arranged abovethe second pump device 17 and comprises a first impeller 24 rotatablyarranged within a first impeller chamber 25. The first impeller issecured to the drive shaft and rotated simultaneously as the secondimpeller by the drive shaft. The first impeller chamber 25 has at leastone impeller chamber inlet 26 arranged on the upper side of the firstpump device 18, i.e. the impeller chamber inlet 26 is arranged facingthe electrical motor and in fluid connection with the space definedwithin the pump housing inside the perforated section 14 of the housing11. The first pump device furthermore comprises two impeller chamberoutlets 32 arranged adjacent to the outer periphery of the firstimpeller in radially opposite positions around the first impeller 24.The first impeller 24 has substantially the same design as the secondimpeller 19 but is mirror-inverted to correspond to the position of thefirst impeller chamber inlet 26. The first impeller generates a flow ofwater through the first pump device 18 from the inlet to the outlet. Theoutlets 32 are curved upwards and connected to first volute tubes 29extending from the outlets to conduits 27 extending within the pumphousing to the outlet pipe 15 past the electrical power source 15 suchthat the water flowing through the conduits 27 cools the electricalpower source when the pump is running. The conduits 27 are arrangedbetween the outlet conduits 23 from the second pump device to providecooling to the electrical motor via the four conduits extending past theelectrical motor.

The conduits 23 in the pump housing from the first pump device and theconduits 27 from the second pump device are either embodied as separateconduits extending through the pump housing around the electric motor tocool the motor, alternatively connected to a common annular spacedefined within the housing around the electrical engine. Fluid is fedvia the conduits to the annular space and exits the space via the outletpipe.

In FIGS. 3A-3C the pump has been configured in the second configuration,and FIG. 3A illustrates a top view of the pump and the position of thecross sectional views in FIG. 3B and FIG. 3C. Most of the differentcomponents of the pump 10 remain the same in both configurations andconsequently the description is focused on the changed features.

In the second configuration, i.e. the configuration where the first pumpdevice 18 and second 17 pump device are arranged in series to provide apump with reduced pumping capacity, fluid enters the pump 10 via thefirst impeller chamber inlet 26. The fluid is flowing through the firstimpeller chamber and exits the first impeller chamber via the twoimpeller chamber outlets such that a flow of fluid is generated. Theflow of fluid through the first pump device 18 is the same in both thefirst and second configuration. Instead of directing the fluid from thefirst pump device towards the outlet pipe 15 as in the firstconfiguration the first impeller chamber outlets are connected to thesecond impeller chamber inlets such that the pumped fluid continues viathe second pump device 17 before it exits the second pump device 17 viathe two second impeller chamber outlets 22 connected via the secondvolute tubes 28 extending from the outlet 22 via conduits 23 to theoutlet pipe 15. In the second configuration only two outlets 22, thesecond volute tubes 28 and conduits 23 are used since the pumped fluidvolume is reduced.

The pump 10 is changed from the first configuration to the secondconfiguration by opening the pump housing bottom structure 12 to accessthe first 18 and second pump device 17 in the lower part of the pumphousing and make it possible to change the configuration within the pumphousing 11.

In order to make it possible to change the pump from the first to thesecond configuration the following modifications need to be done:

The first volute tubes 29 extending from the first pump device outlets32 are removed.

The outlets 32 directed upwards are plugged to redirect the flow offluid downwards towards the second pump device 17. This is in theillustrated embodiment achieved by turning the outlets 32 upside downsuch that the outlets 32 constitute redirecting elements 40 connected tothe first impeller chamber to direct the outlets downwards towards thesecond pump device. The outlets 32, i.e. redirecting elements 40, aredesigned to be removably fitted to the impeller chamber and redirect thefluid to flow from the outer periphery of the impeller of the first pumpdevice downwards towards the second pump device 18. Once the redirectingelements 40 are fitted, the previously used passage that was directedupwards is closed and a new passage extending downwards is opened. Theredirecting elements (outlets 32) are secured to the first pump deviceby screws.

The openings to the conduit 27, or annular recess, extending past theelectrical power source within the pump housing are plugged by pluggingplates 42 designed to fit in the openings to prevent water from flowingin the wrong direction from the conduit 27, or annular space surroundingthe electrical power source. The plugging plates 42 are secured byscrews.

The first impeller chamber outlets are connected to the second impellerchamber inlets to direct water from the first pump device 18 to thesecond pump device 17. This is done by adding a cover element 41,illustrated in FIG. 3D. The cover element 41 is arranged below thesecond pump device 17. The cover element 41 is designed to cover thesecond impeller inlet 21 and provide a reliable sealing that ensuresthat no surrounding water is entering the second pump device 17. Thecover element 41 furthermore comprises connecting means or device 50that open a passage between the first impeller chamber outlet and thesecond impeller chamber inlet, i.e. the cover plate 41 is connected withthe redirecting elements 40 and the first pump device 18. The connectingor device extends upwards towards the first pump device 18 and when thecover element 41 is correctly fitted, the connecting device is fitted inthe opening of the redirecting element 40. The covering element 41ensures that only water from the first pump device 18 is directed to thesecond pump device 17. The cover element 41 is designed to create atleast one connection for the fluid between the redirecting element 40fitted to the first impeller chamber outlet and the second impellerchamber inlet. In the illustrated embodiment in FIG. 3D the coverelement 41 in combination with the pump housing bottom structuretogether covers the second impeller chamber inlet.

In order to revert the pump from the second configuration to the firstconfiguration the added components, i.e. the redirecting elements 40,the plugging plates 42 and the cover element 41 are removed, and thepreviously removed components returned to their original position withinthe pump.

The embodiments described above could be combined and modified indifferent ways without departing from the scope of the invention that isdefined by the appended claims.

1. A pump for fluids, the pump comprising: a pump housing; a powersource enclosed within the housing; a drive shaft connected to the powersource; at least one pump inlet arranged in the pump housing; a pumpoutlet arranged in the pump housing; a first impeller arranged within afirst impeller chamber and configured to be rotated by the drive shaft;and a second impeller arranged within a second impeller chamber andconfigured to be rotated by the drive shaft, the pump being changeablebetween a first configuration in which the first and second impellersare arranged in parallel to provide a high pumping capacity, and asecond configuration in which the first and second impeller are arrangedin series to provide a pump with less pumping capacity than the highpumping capacity.
 2. The pump according to claim 1, wherein the firstand second impellers are arranged at different positions along the driveshaft.
 3. The pump according to claim 1, wherein the power source is anelectrical or hydraulical power source arranged within the pump housing.4. The pump according to claim 1, wherein the housing encloses the powersource and is configured to prevent the fluid reaching the power source.5. The pump according to claim 1, wherein the first impeller chamber, inwhich the first impeller is arranged comprises at least one firstimpeller chamber inlet and at least one first impeller chamber outlet,and the second impeller chamber, in which the second impeller isarranged, comprises at least one second impeller chamber inlet and atleast one second impeller chamber outlet, in the first configuration,the at least one first impeller chamber inlet and second impellerchamber inlet is in fluid connection with the pump inlet, and the atleast one first impeller chamber outlet and second impeller chamberoutlet is connected to the pump outlet, and, in the secondconfiguration, the at least one first impeller chamber outlet is influid connection with the at least one second impeller chamber inlet andthe at least one second impeller chamber outlet is connected to the pumpoutlet.
 6. The pump according to claim 4, wherein the at least one firstand second impeller chamber outlets are connected to conduits extendingwithin the pump housing past the electrical power source to cool theelectrical power source.
 7. The pump according to claim 4, wherein theat least one first impeller chamber outlet and second impeller chamberoutlet is connected to an annular space defined within the housingaround the electrical power source to cool the electrical power source.8. The pump according to claim 1, wherein the first and second impellerchambers each comprises two impeller chamber outlets arranged adjacentto an outer periphery of the first and second impeller in radiallyopposite positions around the impeller.
 9. The pump according to claim8, wherein the outlets of the first impeller chamber are arrangedbetween the outlets of the second impeller chamber in the pump housing.10. The pump according to claim 1, wherein the pump housing comprises ahousing bottom structure removably attached to the housing.
 11. The pumpaccording to claim 1, further comprising at least one redirectingelement, a covering element and at least one plugging plate that arefitted when the pump is operated in the second configuration.
 12. Thepump according to claim 11, wherein the redirecting element and thecovering element are configured to connect the first impeller chamberoutlet with the second impeller chamber inlet.
 13. The pump according toclaim 11, wherein the redirecting element is configured to connect thefirst impeller chamber outlet to the second impeller chamber inlet anddirect the flow of fluid from the first impeller chamber to the secondimpeller.
 14. The pump according to claim 11, wherein the coveringelement has the shape of a plate and is configured to be arrangedcovering the second impeller chamber inlet.
 15. A method for changing apumping capacity of a pump comprising a housing, a power source, a firstimpeller, and a second impeller, the method comprising: changing thepump from a first configuration in which the first impeller and thesecond impeller are arranged in parallel to provide a high pumpingcapacity, to a second configuration in which the first impeller and thesecond impeller are arranged in series to provide the pump with lesspumping capacity than the high pumping capacity.
 16. A method forchanging a pumping capacity of a pump comprising a housing, a powersource, a first impeller, and a second impeller, the method comprising:changing the pump from a second configuration in which the firstimpeller and the second impeller are arranged in series to provide apredetermined pumping capacity, to a first configuration in which thefirst impeller and the second impeller are arranged in parallel toprovide the pump with higher pumping capacity than the predeterminedpumping capacity.